Field of the Invention
The described technology relates generally to a rechargeable battery pack having a configuration in which a battery cell is connected to a protective circuit module.
Description of the Related Art
A rechargeable battery differs from a primary battery in that it can be repeatedly charged and discharged, while the latter is incapable of being recharged.
A low-capacity rechargeable battery is used in small portable electronic devices such as mobile phones, notebook computers, and camcorders, while a high-capacity rechargeable battery can be widely used as a power source for driving a motor of an electric bike, a scooter, an electric vehicle, a fork lift, etc.
Depending on device types using the rechargeable battery, the rechargeable battery may be used as a battery cell or a pack combining a plurality of battery cells.
A typical rechargeable battery pack includes one or more battery cells, a protection circuit module (PCM) that is connected to one or more electrode terminals so as to protect the battery cells, and a protection element for connecting the electrode terminals and the PCM. The PCM is configured to prevent overcharge, over-discharge, overcurrent, and short-circuit of the battery cell.
Further, the protection element is provided between the PCM and the electrode terminal, and may be a resistive element having a positive temperature coefficient (PTC).
As an example of a resistive element, a thermal-cutoff (TCO) element electrically disconnects the electrode terminal from the PCM if the temperature of the battery cell reaches a predetermined risk level, and electrically reconnects them if the temperature reaches a predetermined safe level.
The rechargeable battery pack is provided with a top case between the battery cell and the PCM, and the top case has a bottom surface combined with the battery cell at one side and a top surface supporting a nickel plate at the other side. That is, the TCO is bent after being inserted from the bottom surface of the top case to the top surface thereof.
An outer terminal of the TCO is welded to the nickel plate on the top surface of the top case, and an inner terminal of the TCO is welded to the electrode terminal of the battery cell. Accordingly, a number of parts and thus a number of processes are increased when connecting the TCO to the battery cell, thereby deteriorating productivity. Further, the top case should be manufactured by insert molding the nickel plate, thereby increasing parts cost.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.